Physiological factors such as pH and blood flow are important parameters in determining heat response of tumors. While each of these parameters has been measured separately and invasively by other investigators, the novel aspect of the proposed research arises from the simultaneous, comprehensive and continuous determination of these parameters in vivo. The objectives of the proposed research are 1) to measure simultaneously by noninvasive methods blood flow rate, pH, thermal conductivity and diffusivity, glucose and oxygen consumption, and lactic acid and carbon dioxide production in solid tumors, 2) to assess as a function of temperature the effects of glucose and galactose injections on the above parameters, and 3) to develop dynamic predictive mathematical models based on the physiological data obtained. Experimental methods will involve growing a "tissue isolated" non-metastasizing tumor (W256 carcinoma in Sprague Dawley rats) around a micropore chamber so that the tumor is connected to the host by a single artery and a single vein. A second micropore chamber will be placed in the contralateral subcutaneous space. The pH values will be measured in the interstitial fluids collected in the micropore chambers containing pH electrodes. Temperature, thermal properties and local perfusion in the tumor will be monitored with multiple thermistor probes incorporated by the growing tumor. Concentrations of glucose, lactic acid, oxygen, and carbon dioxide will be measured in the intestitial fluid and the arterial and venous blood of tumors. Total blood flow rate will be measured directly as the amount of blood collected from the tumor vein, while the arterial pressure is maintained constant. Hyperthermia will be induced by infusing for up to 3 hours warm blood (up to 42 C) into the tumor artery. The data obtained will be used to develop a unified theoretical framework relating blood flow, pH, temperature and glucose metabolism, with the overall goal of improving our understanding of tumor physiology.